[Objective] The spatial differentiation patterns of ecological and economic losses in degraded grasslands of West Ujimqin Banner， Inner Monglia Autonomous Region were studied and identify the primary driving factors were identified， in order to provide a scientific basis for decision-making in grassland ecological protection and restoration. [Methods] Taking West Ujimqin Banner as the study area， and based on grassland monitoring data from 2021 to 2023， Landsat 8 OLI， and Sentinel-2 remote sensing images， this study employed a “remote sensing identification + ground verification” technical approach to identify the spatial distribution of grasslands under different degradation levels. An economic loss assessment model incorporating productivity loss and ecosystem service function loss was constructed. Subsequently， methods including principal component analysis and spatial autocorrelation analysis were employed to systematically calculate the scale of economic loss caused by grassland degradation and its spatial heterogeneity. [Results] As of 2023， the degraded grassland area in West Ujimqin Banner reached 8.28×10⁵ hm²， including lightly degraded grassland of 4.28×10⁵ hm² （28.3%）， moderately degraded grassland of 2.66×10⁵hm² （17.6%）， and severely degraded grassland of 1.34×10⁵ hm² （8.8%）， which had not exceeded the critical threshold of irreversible degradation. The total ecological and economic loss caused by grassland degradation reached 2.62×10⁹ yuan， including ecosystem service function loss of 1.50×10⁹ yuan and direct loss from forage yield reduction of 1.12×10⁹ yuan. The loss per unit area was highest in severely degraded grasslands （6，433 yuan/hm²）， while moderately degraded areas contributed the most to the total loss （40.4%）. Principal component analysis revealed that forage yield per unit area， degradation area， and market prices were the dominant driving factors， with a cumulative contribution rate of 89.6%. Economic loss exhibited significant spatial clustering characteristics （Moran’s I=0.426）， with high-loss areas mainly distributed in the northeastern， central-western， and southern regions characterized by high intensity of human activities. [Conclusion] Grassland degradation in West Ujimqin Banner exhibits distinct spatial differentiation characteristics. Moderately degraded grasslands are the primary contributors to economic loss， and human activity intensity is the dominant driving factor. Differentiated protection and governance strategies should be adopted to optimize the regional ecological governance system and achieve sustainable management of grassland ecosystems.